1. noun /ˈpʌzəl/
a) Anything that is difficult to understand or make sense of.
Where he went after he left the house is a puzzle.
Syn: anybodys guess, anyones guess, conundrum, enigma, mystery, brain-teaser, poser, crossword, crossword puzzle, jigsaw, jigsaw puzzle, guessing game, riddle
2. verb /ˈpʌzəl/
See Also: puzzlement
Wikipedia foundation.